1. Field of the Invention
The present invention relates to a web paper cutting position adjusting system and, more particularly, to a system for changing and adjusting the relations of the printing and cutting positions on web paper in a web type offset rotary press.
2. Description of the Prior Art
In the offset rotary press, as is different from a relief rotary press, the web paper is threaded in the so-called "impression throwoff", in which the printing cylinders are thrown off from each other at the stage of preparing the printing of web paper. As a result, the printing of web paper is not performed at this paper threading stage before the start of actual printing. At this actual printing time, the relations between the printing and cutting positions on the web paper are clarified.
In the prior art, therefore, it is exclusively confirmed for each page whether or not the cut pieces discharged from the folded portions are cut in registration with the printed image. If any offset should be between the printing and cutting positions on the web paper, it is adjusted to a corresponding extent by running adjust rollers on the paper being threaded.
In the aforementioned case, according to the prior art, not only the web paper unprinted but threaded but also all the web papers having been threaded till the relations between the printing and cutting positions are adjusted are disposed as imperfections. Still the worse, the adjusting works take a long time to delay the printing works seriously.